The Kampfmesser 42 was a German made dual purpose combat knife. It was issued to the Wehrmacht and Waffen-SS and was used throughout the Second World War. It was designed to be used as both a fighting knife and bayonet. This specific bayonet was longer than the usual bayonet on rifles, and was commonly used as a hand weapon. It was sometimes used as a throwing weapon.
The original article can be found at Kampfmesser 42 and the edit history here.